A number of techniques have been developed to treat stenoses in coronary arteries or occlusions in blood vessels. One of these techniques, angioplasty, is a widely used technique. Angioplasty is a technique for dilating or reopening occluded blood vessels. A typical angioplasty device (also called the angioplasty catheter) includes the use of a guide catheter and a therapeutic device such as a balloon, located near the distal end of the angioplasty catheter. In many cases, the space between the angioplasty catheter and the guide catheter acts as a passage for contrast fluid to travel that exits at the distal end of the guide catheter. During operation, the distal end of the guide catheter is usually positioned in a blood vessel proximal of a stenosis. Then, the angioplasty catheter may be passed through a lumen in the guide catheter such that a balloon is positioned across a stenosis in the blood vessel. The balloon is then inflated for opening the stenosis in the blood vessel. At the time of inflating the balloon or thereafter, medical devices such as stents may also be placed. When the treatment is completed, the balloon is deflated and the angioplasty catheter is removed.
In such conventional medical devices, the cross-section of the guide catheter has to be large enough to create sufficient space between an outer surface of the angioplasty catheter and an inner surface of the guide catheter in order to allow easy flow of the contrast fluid. Also, the cross-section has to be large enough to hold the angioplasty catheter. In some instances, the guide catheter must be much larger than the balloon catheter to accommodate larger devices advanced through the guide catheter during the procedure. The large lumen between the guide catheter and the balloon catheter requires a large quantify of contrast fluid to fill the lumen. While performing medical procedures using conventional medical devices, more contrast fluid may be required to be delivered to a target site, e.g., the stenosis in a blood vessel, and this large volume of the contrast fluid may be deleterious for kidney function. In some instances, the contrast fluid may be delivered near a side branch away from the target site and may get distributed into branching vessels and the effectiveness of the contrast fluid is reduced. Additionally, in some instances the distal end of the guide catheter may be spaced proximally away from the target location in the anatomy such that the contrast fluid exits the guide catheter at a distance away from the target site, requiring the use of more contrast fluid to reach the target site. Furthermore, the large gap between the balloon catheter and the guide catheter may permit undesired blood flow up the guide catheter attributing to blood loss and/or the need for a sealing mechanism to inhibit blood loss.
Accordingly, it is desirable to provide alternative catheter devices and/or methods having improved mechanisms for treating occluded blood vessels, the heart, or other anatomical organs or structures.